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oe1(光电查) - 科学论文

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出版时间
  • 2019
研究主题
  • FSO Communication System
  • Subcarrier Intensity Modulation
  • Atmospheric Turbulence
  • Bit Error Rate
  • Average Irradiance
应用领域
  • Optoelectronic Information Science and Engineering
机构单位
  • Galgotias College of Engineering and Technology
347 条数据
?? 中文（中国） ▾

  • [OSA CLEO: Science and Innovations - San Jose, California (2014..-..)] CLEO: 2014 - Arbitrary Carrier-Envelope Phase Control in a 10 kHz, mJ-Class Amplifier

    摘要： The carrier-envelope phase of every single shot emitted by a 10 kHz, mJ-class amplifier is measured with a fast spectrometer. A novel high-speed actuator allows arbitrary phase control, with closed-loop integrated phase noise on seed oscillator level (98 mrad, 5.10^5 shots, 50 s).

    关键词： Laser amplifiers,Carrier-envelope phase,Ultrafast lasers,Phase control,Amplifier

    更新于2025-09-19 17:15:36

  • Naphthalene and perylene diimides – better alternatives to fullerenes for organic electronics?

    摘要： The LUMO levels of rylene diimides are highly comparable to those of fullerenes but this class of molecules offers tunability of both HOMO and LUMO levels and the related band gap by either simple substitution at the aromatic core or annulation to give expanded p-scaffolds. In this article we highlight the most outstanding achievements during the last decade in terms of charge carrier mobility for organic thin-film and single crystal field-effect transistors as well as photovoltaic performance for both small molecule and polymeric compounds.

    关键词： fullerenes,perylene diimides,organic electronics,photovoltaic performance,naphthalene diimides,charge carrier mobility

    更新于2025-09-19 17:15:36

  • Janus Chromium Dichalcogenides Monolayers with Low Carrier Recombination for Photocatalytic Overall Water-Splitting under Infrared Light

    摘要： Photocatalytic overall water-splitting is known as one of most promising methods to alleviate energy crisis. Searching for stable and efficient photocatalysts plays a critical role in this process. Here, we propose a novel class of Janus chromium dichalcogenides (CrXY, X/Y = S, Se, Te) monolayers serving as efficient photocatalysts for overall water-splitting under infrared light irradiation. We reveal that these Janus monolayers harbor an intrinsic dipole, which promotes the spatial separation of photo-generated carriers. More significantly, these systems exhibit suitable band gaps as well as band edge positions, enabling preeminent infrared optical absorption and high carrier mobility. Furthermore, the nonradiative recombination of photoinduced charge carriers in CrXY monolayers are evaluated based on time-domain density functional theory. The obtained long-lived excited carriers (~ 2 ns) are even comparable with that in transition-metal dichalcogenides heterostructures, which benefits for the photocatalytic reaction with high efficiency. Our results provide a new guidance for designing brand new photocatalytic systems with broad optical absorption and low carrier recombination.

    关键词： infrared light,first principles calculations,carrier recombination,Janus chromium dichalcogenides,photocatalytic water-splitting

    更新于2025-09-19 17:15:36

  • A novel hydrogenated boron–carbon monolayer with high stability and promising carrier mobility

    摘要： Although immense research on the extension of the two-dimensional (2D) material family has been carried out, 2D materials with a satisfactory band gap, high carrier mobility, and outstanding thermodynamic stability under ambient conditions are still limited. In this work, using first principles calculations, we proposed new 2D ternary materials consisting of C, B, and H atoms, namely hexagonal-BCH (h-BCH) and tetragonal-BCH (t-BCH). Both phonon calculations and ab initio molecular dynamics simulations show that these proposed sheets are thermodynamically stable phases. The electronic structure calculations indicate that h-BCH and t-BCH sheets are semiconductors with a band gap of 2.66 and 2.22 eV, respectively. Remarkably, the h-BCH (t-BCH) sheet exhibits electron mobility as high as 7.41 × 10^3 (1.09 × 10^3) cm^2 V^{-1} s^{-1}, which is higher than that of the MoS2 monolayer, though the hole mobility is about one (two) order of magnitude lower. Equally important is the fact that the position of both the conduction and valence band edges of the h-BCH sheet matches well with the chemical reaction potential of H2/H+ and O2/H2O, giving a 2D photocatalyst as a potential candidate for overall visible-light-driven water splitting. Therefore, the designed h-BCH and t-BCH monolayers have promising applications in future electronics and photocatalysts.

    关键词： 2D materials,boron-carbon-hydrogen,photocatalysis,first principles calculations,carrier mobility

    更新于2025-09-19 17:15:36

  • Widening the 2D/3D Perovskite Family for Efficient and Thermal-Resistant Solar Cells by the Use of Secondary Ammonium Cations

    摘要： While 2D/3D layered perovskites have been the object of comprehensive research principally focused on increasing the long-term stability observed in 3D perovskites, significant opportunities still exist concerning the application of different kinds of cations outside the sphere of primary amines, which are the cations most usually applied. Our results demonstrate that the materials and the solar cells prepared with dipropylammonium iodide (DipI), a bulky secondary ammonium cation of small size, lead to obtaining materials that are not only efficient and thermodynamically stable but also robust toward heat stress. Time-resolved studies indicate longer carrier lifetime for 2D/3D layered perovskites fabricated with this bulky cation than for systems based on bulky primary ammonium cations, which allowed us to obtain PCE = 12.51% (n = 10), 15.78% (n = 50), and 17.90% (n = 90). We determine that the concentration of perovskite material after 240 min at 100 °C is up to 575% greater in the 2D/3D perovskite (n = 10) than that observed in 3D perovskite films. The material stability also improves the thermal stability of the photovoltaic devices, presenting an efficiency drop of just 4% for n = 50 and n = 10 after thermal annealing while the performance drop for reference 3D samples in the same conditions was greater than 80%.

    关键词： carrier lifetime,2D/3D perovskites,solar cells,thermal stability,secondary ammonium cations

    更新于2025-09-19 17:13:59

  • Ultrafast Charge Carrier Dynamics and Nonlinear Optical Absorption of InP/ZnS Core-Shell Colloidal Quantum Dots

    摘要： Understanding of ultrafast carrier dynamics in InP/ZnS colloidal quantum dots (QDs) is essential for their optoelectronic applications. In this paper, we have successfully fabricated high-quality InP/ZnS core-shell QDs with quantum yield (QY) of 47%. Time resolved photoluminescence (TRPL), femtosecond transient absorption (TAS) measurements were performed to characterize the carrier injection, relax and transition process in the InP/ZnS QDs. It is found that the photoexcited carrier first injected to ZnS shell in 2 ps, then relaxed to alloyed layer between ZnS shell and InP core in 7.4 ps, next relaxed to different energy levels in InP core in about 170 ps, finally recombined by charged and neutral excitons transition in 4.1 ns and 26.7 ns, respectively. Additionally, the two-photon absorption (TPA) coefficient obtained from Z-scan measurement indicates that InP/ZnS QDs possess good nonlinearly optical properties. Our research is significant for the improvement and engineering of InP/ZnS QDs based materials for optoelectronic applications.

    关键词： quantum dots,InP/ZnS,ultrafast carrier dynamics,nonlinear optical absorption,optoelectronic applications

    更新于2025-09-19 17:13:59

  • Elucidation of Donor:Acceptor Phase Separation in Nonfullerene Organic Solar Cells and Its Implications on Device Performance and Charge Carrier Mobility

    摘要： In bulk-heterojunction solar cells, the device performance strongly depends on the donor and acceptor properties, the phase separation in the absorber layer, and the formation of a bicontinuous network. While this phase separation is well explored for polymer:fullerene solar cells, only little is known for polymer:nonfullerene acceptor solar cells. The main hurdle in this regard is often the chemical similarity of the conjugated polymer donor and the organic nonfullerene acceptor (NFA), which makes the analysis of the phase separation via atomic force microscopic (AFM) phase images or conventional transmission electron microscopy difficult. In this work, we use the donor polymer PTB7-Th and the small molecule acceptor O-IDTBR as the model system and visualized the phase separation in PTB7-Th:O-IDTBR bulk-heterojunctions with different donor:acceptor ratios via scanning transmission electron microscopy (STEM) high-angle annular dark-field (HAADF) images and electron energy loss spectroscopy (EELS) based elemental mapping, which resulted in a good contrast between the donor and the acceptor despite very low differences in the chemical composition. AFM as well as grazing-incidence wide-angle X-ray scattering (GIWAXS) investigations support the electron microscopic data. Furthermore, we elucidate the implications of the phase separation on the device performance as well as charge carrier mobilities in the bulk-heterojunction layers, and a high performance of the solar cells was found over a relatively broad range of polymer domain sizes. This can be related to the larger domain sizes of the acceptor phase with higher amounts of O-IDTBR in the blend, while the polymer donor phase still forms continuous pathways to the electrode, which keeps the hole mobility at a relatively constant level.

    关键词： nanomorphology,organic photovoltaics,charge carrier mobility,bulk-heterojunction,scanning transmission electron microscopy

    更新于2025-09-19 17:13:59

  • Ultrafast acoustic phonon scattering in CH <sub/>3</sub> NH <sub/>3</sub> PbI <sub/>3</sub> revealed by femtosecond four-wave mixing

    摘要： Carrier scattering processes are studied in CH3NH3PbI3 using temperature-dependent four-wave mixing experiments. Our results indicate that scattering by ionized impurities limits the interband dephasing time (T2) below 30 K, with strong electron-phonon scattering dominating at higher temperatures (with a time scale of 125 fs at 100 K). Our theoretical simulations provide quantitative agreement with the measured carrier scattering rate and show that the rate of acoustic phonon scattering is enhanced by strong spin-orbit coupling, which modifies the band-edge density of states. The Rashba coefficient extracted from fitting the experimental results (γc = 2 eV ?) is in agreement with calculations of the surface Rashba effect and recent experiments using the photogalvanic effect on thin films.

    关键词： electron-phonon scattering,carrier scattering,CH3NH3PbI3,four-wave mixing,Rashba effect

    更新于2025-09-19 17:13:59

  • [IEEE 2018 Asia Communications and Photonics Conference (ACP) - Hangzhou, China (2018.10.26-2018.10.29)] 2018 Asia Communications and Photonics Conference (ACP) - Bias Modulation Characteristic Analysis Using a Uni-Traveling-Carrier Photodiode

    摘要： We theoretically studied the photodiode bias modulation technology. Based on one uni-traveling-carrier photodiode structure, the modulation bandwidth can reach 25 GHz at a 150 GHz subcarrier signal when the incident optical power is 12.93 dBm.

    关键词： Radio-over-Fiber (RoF) links,photodiode(PD) bias modulation,uni-traveling-carrier photodiode (UTC-PD)

    更新于2025-09-19 17:13:59

  • [IEEE 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz 2018) - Nagoya (2018.9.9-2018.9.14)] 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Optically Pumped Mixing in Photonically Integrated Uni- Travelling Carrier Photodiode

    摘要： We report the first demonstration of optically pumped mixing using a monolithically integrated photonic chip. On that chip, uni-traveling carrier photodiodes (UTC-PDs) were monolithically integrated with two lasers to generate the optical heterodyne that will drive the optically pumped mixing. The two DFB lasers wavelength spacing was tuneable from 70.5 GHz to 92.4 GHz. When an RF signal at 70 GHz was supplied to the UTC-PD with the optimum voltage bias, the UTC-PD successfully down-converted the RF signal to an intermediate frequency (IF) that was tuneable from 0.5 GHz to 16.4 GHz. These results demonstrate the potential of this photonic integrated circuit in spectroscopy, sensing and as millimeter wave wireless receivers.

    关键词： photonic integrated circuit,heterodyne,millimeter wave,optically pumped mixing,uni-traveling carrier photodiode

    更新于2025-09-19 17:13:59